This invention relates to a device for discriminating the attitude of parts according to certain shape information of the parts.
A conventional method for discriminating the attitude of parts comprises the steps of: examining all the attitudes and shapes of the parts in the course of conveying; positioning detection elements or signal transmission members at a typical portion of each attitude; and discriminating the attitude of the parts. In a rectangular part W having a notched portion at a corner thereof as shown in FIG. 1, for example, all the necessary attitudes of the part W can be discriminated by positioning a detection element or a signal transmission member at points 2b and 2c respectively when the arrival of the part W has been detected at a point 2a in FIG. 2. Namely, the attitude of the part corresponding to W.sub.1 (FIG. 2a) is in a detecting state at both the points 2b and 2c, that of W.sub.2 (FIG. 2b) is in a non-detecting state at both 2b and 2c, that of W.sub.3 (FIG. 2c) is in a non-detecting state at 2b and in a detecting state at 2c, and that of W.sub.4 (FIG. 2d) is in a detecting state at 2b and in a non-detecting state at 2c.
This method, however, is premised on the assumption that all the attitudes and shapes for transmitting the detecting portion are already known. Therefore, even if the attitudes and shapes of the part W are detected at 2a, 2b and 2c, when a part W.sub.5 in the attitude shown in FIG. 3 gets mixed in with the other parts, the attitude of the part W.sub.5 cannot be discriminated as the detecting state thereof is entirely the same as that of the part W.sub.2 in FIG. 2b. The work to search for the above-noted typical portion becomes more troublesome as the shape of the parts becomes more complicated. As illustrated, the conventional method lacks flexibility and takes much time, labor and cost for adjustment in case the shape of the parts is changed and, therefore, the conventional method is not suitable for a variety of differently shaped parts produced in small quantity.